High-frequency heating device having reflecting plates for distribution of high frequency microwaves

ABSTRACT

A high-frequency heat cooling device in which high-frequency electric wave is introduced from a high-frequency oscillating power source into a heating chamber through a power supply opening constructed in a ceiling wall of the heating chamber, via a waveguide, comprising a plurality of reflecting plates formed by cutting the ceiling wall located at an end of said waveguide and inclining the plates in a suitable angle while the same number of power supply openings as the number of the plates being provided.

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a high-frequency heat cooking device(electronic range) and more particularly to a high-frequency heatcooking device provided with an improved high-frequency electric wavesupply port constructed in a waveguide.

2. Prior art

This type of high-frequency heat cooking device known in the prior arthas been constructed in such a manner that microwave energy isoscillated in a high-frequency oscillating power source, e.g. amagnetron and supplied into a range box from a power supply openingcostructed on the ceiling wall of a heating chamber (cooking chamber)through a waveguide. With such a device based, on the prior art, anobject of cooking must be irradiated evenly by the microwave energy in auniformly distributed electric field. For this purpose, a stirrer bladeis equipped in the ceiling of the heating chamber to agitatehigh-frequency electric waves. According to another system known in theprior art, a post comprising a dielectric material is arranged in asuitable position within the waveguide to maintain uniform distributionof the electric field. However, these high-frequency heat cookingdevices known in the prior art brought about increased number of partsand complicated structure.

One object of the present invention is to provide a low costhigh-frequency heat cooking device that is suitable for mass productionby introducing extremely simple and low-cost machining means andeliminating unnecessary additional matters. Another object of thepresent invention is to irradiated high-frequency electric wave from ahigh-frequency oscillating power source onto a cooking object located ina heating chamber. Still another object of the present invention is toprevent dispersion of an electric wave by collecting it at a powersupply port constructed with reflective plates. According to anotherobject of the present invention, these reflective plates are formed bypunching square tongues by pressing the ceiling wall of the heatingchamber (cooking chamber) and bending these tongues in suitable anglestowards the waveguide.

SUMMARY OF THE INVENTION

According to the present invention, high-frequency electric wave isgenerated in a high-frequency oscillating power source and introducedand supplied into a heating chamber through a power supply openingconstructed in the ceiling wall of the heating chamber via a waveguide,with a high-frequency heat cooking device. A plurality of reflectingplates are cut and bent in the ceiling wall of the heating chamberlocated at an end part of said waveguide and inclined towards thewaveguide in suitable angles. At the same time, the same number of powersupply openings as the number of the reflecting plates is provided withthe high-frequency heat cooking device according to the presentinvention.

It is preferable to incline the reflecting plates, for introducinghigh-frequency electric wave generated in the high-frequency oscillatingpower source into the heating chamber through power supply openingsconstructed in the ceiling wall of the heating chamber located at an endof the waveguide, to suitable positions where the introduction of thehigh-frequency electric wave is not disturbed at the said power sourceopenings, in suitable angles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique view of important parts in a high-frequency heatingdevice according to the present invention.

FIG. 2 shows section of a high-frequency wave supply port.

FIG. 3 is a sectional view of line III--III in FIG. 2.

FIG. 4 is an explanatory plan view of a high-frequency wave supply port.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention is detailed in the followingparagraphs referring to the attached drawings.

FIG. 1 shows an oblique view of important parts of the basic structureafter removing an outer cover of the high-frequency heat cooking deviceaccording to the present invention, in which 1 shows a housing, 2represents a heating chamber in said housing 1, 3 a backplate attachedto the rear part of housing 1 and 4 a front frame to which an open/closedoor, although not illustrated in FIG. 1, is hinged in a freeopening/closing manner. No. 5 is a long square waveguide having aninverted T cross section and constructed in a ceiling wall 6 of heatingchamber 2 while 7 representing a magnetron mounted at one end of saidwaveguide 5.

FIG. 2 is an enlarged sectional view of waveguide 5 mounted by spotwelding onto the ceiling wall 6 of the heating chamber. The magnetron 7is fixed at the right end of the waveguide 5. A post 8 is protrudinglyprovided in the inner part of the left end of said waveguide 5, on theceiling face. Long square elevated tongues 9, 9a, 9b are pressed out atthree positions, namely the left longitudinal end of the waveguide 5 andthe upper and left parts of FIG. 3, in the ceiling wall 6 of the heatingchamber. These positions are separated from centerlines of the post 8X-X' and Y-Y' by specified interval L, as shown in FIGS. 3 and 4. Thesetongues are bent in an angle of about 45° towards the waveguide asreflecting plates. Thus, there are long square windows 10, 10a, 10b areopened where the reflecting plates were located before being pressed, inthe same shape as the reflecting plates. These windows 10, 10a, 10b actas the power supply openings.

According to the present invention as described above, electric wave isoscillated from the oscillating unit (antenna) 11 of the magnetron, etc.Namely a high-frequency oscillating power source and transmitted fromthe right to the left in the figure, namely in longitudinal direction ofthe waveguide, rectified at the post, arrives at the reflecting plateserected by an angle of 45° in three directions, is reflected by about90° and fed onto an object of cooking located in the heating chamberthrough the power supply openings as high-frequency electric wave energyfor heating. These reflecting plates are cut in substantially the samedimensions at a part of the ceiling wall of the heating chamber, erectedby pressing and bent in an angle of about 45° thus forming reflectingplates integrated with the ceiling in the heating chamber. Accordingly,no additional materials are required for the reflecting plates whilesaving resources. In addition, work processes are also omitted comparedto a case where the reflecting plates composed of other materials areattached. Therefore, the present invention provides many practicaladvantages such as reduced wages, easier mass production and low costbecause of simpler structure.

What is claimed is:
 1. A high-frequency microwave heating device inwhich high-frequency microwaves are generated by a high-frequencyoscillating power source, comprising:a heating chamber for placing anobject to be cooked therein; a waveguide connecting said high-frequencypower source to said heating chamber, wherein said waveguide includes apower supply opening directly connected to said heating chamber and aprojection positioned directly above and extending to said power supplyopening, wherein said power supply opening includes a plurality of powersupply apertures, each of said apertures surrounds said projection witha substantially same distance therebetween and is provided with aninclined reflecting plate extending into said waveguide such thatmicrowaves from said high-frequency oscillating power source arereflected by said projection and said inclined reflecting plates andtransmitted uniformly into said heating chamber.
 2. The high-frequencymicrowave heating device according to claim 1, wherein said projectionis a semi-spherical projection.
 3. The high-frequency microwave deviceaccording to claim 1, wherein the number of said apertures is three. 4.The high-frequency microwave heating device according to claim 1,wherein an inclined angle of each inclined reflecting plate is 45°. 5.The high-frequency microwave heating device according to claim 1,wherein each aperture has a shape of rectangle.
 6. The high-frequencymicrowave heating device according to claim 1, wherein said power supplyopening is provided in a wall common to said waveguide and said heatingchamber.